1. Technical Field
The present disclosure relates to crosslinked fibers, and more particularly to the use of click chemistry to form the crosslinked fibers using transition metal ions, methods of preparing such fibers, and surgical devices made from such fibers.
2. Background of Related Art
Methods for making monofilaments that are suitable to fabricate surgical articles, such as sutures, generally include the steps of extruding at least one bioabsorbable or nonbioabsorbable polymer to provide filaments, drawing or stretching the solidified filaments to achieve molecular orientation, and annealing the drawn filaments to relieve internal stresses.
Various spinning methods may be employed, such as melt spinning, gel spinning, wet or dry spinning, and reaction spinning. Melt spinning uses heat and potentially shear to melt the fiber-forming polymer to a viscosity suitable for extrusion through the die or spinneret. After exiting the die, the fiber solidifies by cooling in air or a suitable chilled fluid bath. In solvent spinning, the fiber-forming polymer is dissolved in a suitable organic solvents or solvent mixture to result in a fluid with suitable viscosity for extrusion through a spinneret. The difference between wet and dry spinning is the means by which the fiber solidifies. In dry spinning, the fiber solidifies as the solvent evaporates under a stream of air or inert gas. In wet spinning, the fiber forms by precipitating from solution as a result of dilution in a non-solvent bath or chemical reaction with a crosslinker in the solvent bath. Gel spinning refers to a process similar to solvent spinning except that the polymer is not fully dissolved in the solvent—a high polymer content is used in the process. The chains of the partially solvated polymer are aligned by the shear during the extrusion process. The filaments are further drawn as they are passed through a gas drying then a wet precipitating bath. The resulting fibers have an unusually high degree of alignment and high tensile strength relative to conventional melt or solvent spinning techniques. Reaction spinning involves the formation of filaments from reactive polymers or prepolymers and monomers that are further polymerized and cross-linked during the extrusion process or after the fiber or filament is formed.
Click chemistry refers to a collection of reactions capable of forming a highly reliable molecular connection in solution or bulk state. Click chemistry reactions may be highly selective, high yield reactions which should not interfere with one another as well as other reactions.
It would be desirable to make filaments useful in making surgical devices by extruding a mixture containing first and second precursors functionalized for crosslinking by click chemistry using a transition metal ion catalyst.